The present invention relates to the delivery of medical devices and, in particular, occlusion elements. Occlusion elements, such as coils, are delivered to occlude vascular regions and malformations for various reasons. For example, occlusion elements, such as coils, may be delivered into an aneurysm to occlude the aneurysm. Other uses of occlusion elements include treatment of AVM""s and other malformations.
The occlusion element is coupled to a delivery element with a material which is dissolvable with a fluid. The material forms a dissolvable connection between the delivery element and the occlusion element. The occlusion element is advanced through the patient""s vascular system and, at the appropriate time, the material is dissolved. The dissolvable material is preferably dissolved with a fluid which is delivered to the material through the delivery element or through a tube positioned in the delivery element. The fluid may be delivered, withdrawn or otherwise circulated around the material with the tube and delivery element in any suitable manner. Alternatively, the material may be dissolved with the patient""s own blood. Finally, the fluid may also be contained within the delivery element but separated from the material until the desired time.
The occlusion element may be embedded in the material. For example, the occlusion element may have a coil, a plurality of filaments, a ball or a cage embedded in the material. The embedded portion may also be in an expanded position when embedded in the material and in a collapsed position after the material is dissolved. For example, the embedded portion may be a stacked coil when collapsed and a stretched coil when embedded in the material. The delivery element may also have a portion embedded in the material such as a number of filaments.
A blocking element may also be provided which protects part of the dissolvable material from exposure to blood or other fluids. The blocking element may be positioned within a cavity in the material. The cavity may be a throughhole through which the fluid is delivered when dissolving the material. The blocking element may also help to protect the connection from kinking and other mechanical disturbances which occur when advancing the occlusion element through small, tortuous vessels. The blocking element can prevent inadvertent mechanical detachment when the device is bent or otherwise deformed during advancement through the patient.
A flexible sheath may also be positioned over the material to protect the material. The sheath may be solid or may have openings or slits therein to promote flow through the sheath when dissolving the material. The delivery element may also have a fluid distributing portion which distributes the fluid for dissolution of the material.
The occlusion element itself may also have a blocking portion which prevents contact between the patient""s blood and the material thereby inhibiting premature dissolution of the material. The blocking portion may be a plug of material such as solder.
These and other advantages of the invention will become apparent from the following description of the preferred embodiments, claims and drawings.